Methods and systems for evaluating hearing using cross frequency simultaneous masking

ABSTRACT

A method for conducting a cross frequency simultaneous masking (xF SM) test begins with generating a signal probe and a masker probe. The center frequencies of the signal and masker probes are separated by a fixed frequency ratio. An xF SM curve is generated by sweeping the signal and masker probes across a given frequency range, while maintaining the fixed frequency ratio between the two. While sweeping, the masker probe is maintained at a pre-determined masker amplitude or a series of pre-determined masker amplitudes. The amplitude of the signal probe is adjusted in response to a series of user inputs, which are then interpolated to generate the xF SM curve. Additionally, while sweeping, the signal probe can be maintained at one or more pre-determine amplitudes and the amplitude of the masker probe adjusted in response to user inputs, which are then interpolated to generate the xF SM curve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/847,472, filed Apr. 13, 2020, which is hereby incorporated byreference, in its entirety and for all purposes.

FIELD OF INVENTION

This invention relates generally to the field of psychophysics,audiology, audio engineering and digital signal processing (DSP), andmore specifically pertains to methods and systems for evaluating hearingusing cross frequency simultaneous masking.

BACKGROUND

Various behavioral methods have been developed in psychophysics toobtain psychometric data from observers, e.g., to measure a person'shearing ability. For example, conventional methods include the method oflimits, the method of constant stimuli, the method of adjustment, aswell as forced choice methods. In the context of measuring an observer'shearing threshold, Bekesy developed a method of “continuous adjustment”called “Bekesy tracking” [Bekesy, G. v., A new audiometer, ActaOto-Laryngologica, 35, 41, 1-422. (1947)]. By way of a simple binaryinteraction of the user (pressing or releasing a single button), aparameter, i.e. the amplitude, of a sound stimulus is constantlyincreased or decreased resulting in an oscillation around a threshold.The threshold level can then be estimated from the points of userinteraction occurring above and below the threshold.

A “sweeping” Bekesy tracking paradigm represents a variant of thatgeneral method, where a second parameter of the stimulus (e.g.frequency) is constantly changed so that the level of the perceptualthreshold is traced along a range of values of that parameter of thestimulus. Originally developed for estimating pure tone auditorythresholds, the general mechanics of the Bekesy method, i.e. thecontinuous adjustment of parameters of a stimulus based on userinteraction, have also been applied in other contexts, such assimultaneous masking suprathreshold tests, e.g. for estimatingpsychophysical tuning curves (PTC) and masked threshold (MT) curves.[Sek, A., Alcantara, J., Moore, B. C. J., Kluk, K., & Wicher, A.,Development of a fast method for determining psychophysical tuningcurves, International Journal of Audiology, 44(7), 408-420. (2005)].Bekesy audiometry has been recognized as a useful diagnostic tool inclinical audiology [see, e.g., Granitz, D. W. “An evaluation ofdiagnostic parameters of Bekesy audiometry”, LSU Historical DissertationTheses 2052 (1971)].

In a Bekesy tracking/continuous adjustment paradigm, for example, a useris tasked with pressing a button when he hears a sound and releasing thebutton when he does not. As long as the button is pressed, theparameter, i.e. the amplitude, of the stimulus is continuously reduceduntil the user releases the button. When the button is released, theparameter, i.e. the amplitude, of the stimulus is increased. As a resultof this procedure, the parameter of the stimulus should continuouslyoscillate around the threshold level of a user at a given frequency.

Owing to its intuitive and engaging character, this method of continuoususer-controlled adjustment of the parameter of the stimulus lends itselfparticularly well for (but is not limited to) consumer (e.g. mobiledevice) implementations of psychometric tests, such as audiometrichearing tests. Users can quickly learn the task and are not required todirectly look at the device during a test, such that the user'scontinuous engagement allows for a large body of data to be collected.

In the context of using a sweeping Bekesy paradigm for a simultaneousmasking threshold test, the test duration can be reduced to only a fewminutes per ear for a given center frequency. Although this is arelatively short time for testing at a single center frequency, it wouldbe ideal to test a user's hearing across a range of audible frequenciesto get a more comprehensive assessment of user hearing health as itpertains to simultaneous masking. However, using conventional MT or PTCBekesy sweeping techniques, this would take an amount of timeimpractical for a consumer context, leading to user fatigue andinaccurate test results. For example, testing at center frequencies 500Hz, 1 kHz, 2 kHz, 4 kHz and 6 kHz for each ear to cover a broad range ofthe audible spectrum could take up to half an hour. Accordingly, it isan object of the disclosure to provide systems and methods for a morerapid test encompassing a wide range of audible frequencies using asimultaneous masking paradigm.

SUMMARY OF THE INVENTION

According to an aspect of the present disclosure, provided are methodsand systems for evaluating hearing using cross frequency simultaneousmasking. A signal probe and a masker probe are generated, wherein acenter frequency of the signal probe and a center frequency of themasker probe are separated by a first fixed frequency ratio; for a givenfrequency range, a first xF SM curve is generated by: sweeping thesignal probe and the masker probe across the given frequency range whilemaintaining the first fixed frequency ratio between the signal probe andthe masker probe; maintaining the masker probe at a pre-determinedmasker amplitude; adjusting the amplitude of the signal probe inresponse to a series of user inputs; and interpolating the series ofuser inputs to generate the first xF SM curve.

In an aspect of the disclosure, the first xF SM curve is an xF MT curve,and the method further comprises: constructing, based on the xF MTcurve, one or more masked threshold curves across a range of audiblefrequencies, one or more psychophysical tuning curves, or a pure tonethreshold audiogram.

In a further aspect of the disclosure, the method further comprises, forthe given frequency range, generating a second xF SM curve by: sweepingthe signal probe and the masker probe across the given frequency rangewhile maintaining a second fixed frequency ratio between the centerfrequency of the signal probe and the center frequency of the maskerprobe; adjusting the amplitude of the signal probe in response to asecond series of user inputs; and interpolating the second series ofuser inputs to generate the second xF SM curve.

In a further aspect of the disclosure, the second fixed frequency ratiois different than the first fixed frequency ratio.

In a further aspect of the disclosure, the method further comprisesinterpolating between the first xF SM curve, generated for the firstfixed frequency ratio, and the second xF SM curve, generated for thesecond fixed frequency ratio; and based on the interpolation,constructing one or more masked threshold curves across a range ofaudible frequencies, one or more psychophysical tuning curves, or a puretone threshold audiogram.

In a further aspect of the disclosure, the second fixed frequency ratiois the same as the first fixed frequency ratio and the method furthercomprising: averaging the first xF SM curve and the second xF SM curveto generate a first averaged xF SM curve for the first fixed frequencyratio.

In a further aspect of the disclosure, the method further comprises, forthe given frequency range, generating a second averaged xF SM curve fora fixed frequency ratio different than the first fixed frequency ratio;interpolating between the first averaged xF SM curve and the secondaveraged xF SM curve; and based on the interpolation, constructing amasked threshold curve, a psychophysical tuning curve, or an audiogram.

In a further aspect of the disclosure, the method further comprisesperforming a threshold hearing test or receiving user input to estimatethe pre-determined masker amplitudes of the masker probe, wherein themasker is audible to a given listener of the xF SM test.

In a further aspect of the disclosure, adjusting the amplitude of thesignal probe in response to the user input comprises: increasing theamplitude of the signal probe in response to a determination that theuser input is received; and decreasing the amplitude of the signal probein response to a determination that the user input is not received.

In a further aspect of the disclosure, the amplitude of the signal probeis continuously adjusted in response to the series of user inputs.

In a further aspect of the disclosure, the method further comprisesproviding the sweeping signal probe and masker probe to a user of anaudio output device as an auditory stimulus, wherein the series of userinputs comprises user responses indicating the user's perception of theauditory stimulus.

In a further aspect of the disclosure, the user input comprises userresponses obtained in response to a Bekesy testing paradigm.

In a further aspect of the disclosure, the given frequency rangecomprises at least a portion of the audible spectrum.

In a further aspect of the disclosure, the given frequency range is from500 Hertz (Hz) to 6 kilohertz (kHz).

In a further aspect of the disclosure, the cross frequency simultaneousmasking test is a cross frequency masked threshold test; the signalprobe is a tone signal; and the masker probe is a noise signal.

In a further aspect of the disclosure, the cross frequency simultaneousmasking test is a cross frequency psychophysical tuning test; the signalprobe is a masking signal; and the masker probe is a tone signal.

In a further aspect of the disclosure, the first fixed frequency ratiois between 1.0 and 1.5.

In a further aspect of the disclosure, the first fixed frequency ratiois between 1.0 and 1.5; and the second fixed frequency ratio isdifferent from the first fixed frequency ratio.

In a further aspect of the disclosure, the cross frequency simultaneousmasking curve is used to calculate one or more parameters for aprocessing function.

In a further aspect of the disclosure, sweeping the signal probe and themasker probe across the given frequency range comprises: sweeping froman intermediate frequency value to a maximum frequency value, themaximum frequency value greater than the intermediate frequency value;sweeping from the maximum frequency value to a minimum frequency value,the minimum frequency value less than the maximum frequency value andless than the intermediate frequency value; and sweeping from theminimum frequency value to the intermediate frequency value.

Unless otherwise defined, all technical terms used herein have the samemeaning as commonly understood by one of ordinary skill in the art towhich this technology belongs.

The term “hearing test”, as used herein, is any test that evaluates auser's hearing health, more specifically a hearing test administeredusing any transducer that outputs a sound wave.

The term “simultaneous masking”, as used herein, is a property of thehuman auditory system where some sounds become inaudible in the presenceof other sounds (i.e. maskers).

The term “simultaneous masking test”, as used herein, is any test inwhich a masker probe is played simultaneously with a signal probe inorder to test hearing ability. This may, for example, take the form of apsychophysical tuning curve (PTC), a masked threshold (MT) curve, or across frequency simultaneous masking test (xF SM).

The terms “xF MT test” and “xF MT curve”, as used herein, are subsets ofthe terms “xF SM test” and “xF SM curve”, respectively.

The term “hearing thresholds”, as used herein, is the minimum soundlevel of a pure tone that an individual can hear with no other soundpresent. This is also known as the ‘absolute threshold’ of hearing.Individuals with sensorineural hearing impairment typically displayelevated hearing thresholds relative to normal hearing individuals.Absolute thresholds are typically displayed in the form of an audiogram.

The term “headphone”, as used herein, is any earpiece bearing atransducer that outputs sound waves into the ear. The headphone may be awireless hearable, a corded or wireless headphone, a hearable device, orany pair of earbuds.

The term “sound personalization algorithm”, as used herein, is definedas any digital signal processing (DSP) algorithm that processes an audiosignal to enhance the audibility or clarity of the signal to a listener,or otherwise provides specific benefits to an individual listener, e.g.by matching individual sound preference(s). The DSP algorithm may be,for example: an equalizer, an audio processing function that works onthe sub-band level of an audio signal, a multi-band compressive system,or a non-linear audio processing algorithm.

The term “audio output device”, as used herein, is defined as any devicethat outputs audio, including, but not limited to: mobile phones,computers, televisions, hearing aids, headphones, smart speakers,hearables, and/or speaker systems.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features of the disclosure can be obtained, a moreparticular description of the principles briefly described above will berendered by reference to specific embodiments thereof, which areillustrated in the appended drawings. Understand that these drawingsdepict only exemplary embodiments of the disclosure and are nottherefore to be considered to be limiting of its scope, the principlesherein are described and explained with additional specificity anddetail through the use of the accompanying drawings in which:

FIG. 1A illustrates the deterioration of hearing thresholds with age;

FIG. 1B illustrates masked threshold curve age trends;

FIGS. 2A-B illustrate constructed PTC and MT curves using Bekesytracking;

FIG. 3 illustrates an exemplary flowchart for conducting a crossfrequency (xF) simultaneous masking (SM) test;

FIGS. 4A-C illustrate an example of a cross frequency simultaneousmasking (xF SM) paradigm for an MT test, which is a subset of an xF SMtest;

FIGS. 5A-B illustrate exemplary Bekesy testing data of an xF SM testusing a noise probe to signal probe frequency ratio of 1.5;

FIGS. 6A-B illustrates three sets of exemplary testing data, comparingconventional MT testing data in the left and right ears across a rangeof frequencies (depicted in FIG. 6A) with xF SM testing data in the leftand right ears in the same frequency range using noise to signal probefrequency ratios of 1, 1.25 and 1.5 (depicted in FIG. 6B); and

FIGS. 7A-B illustrate a juxtaposition of MT testing data with xF SMdata.

DETAILED DESCRIPTION

Various embodiments of the disclosure are discussed in detail below.While specific implementations are discussed, it should be understoodthat this is done for illustration purposes only. A person skilled inthe relevant art will recognize that other components and configurationsmay be used without parting from the spirit and scope of the disclosure.Thus, the following description and drawings are illustrative and arenot to be construed as limiting the scope of the embodiments describedherein. Numerous specific details are described to provide a thoroughunderstanding of the disclosure. However, in certain instances,well-known or conventional details are not described in order to avoidobscuring the description. References to one or an embodiment in thepresent disclosure can be references to the same embodiment or anyembodiment; and, such references mean at least one of the embodiments.

Reference to “one embodiment” or “an embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the disclosure. Theappearances of the phrase “in one embodiment” in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. Moreover, various features are described which may beexhibited by some embodiments and not by others.

The terms used in this specification generally have their ordinarymeanings in the art, within the context of the disclosure, and in thespecific context where each term is used. Alternative language andsynonyms may be used for any one or more of the terms discussed herein,and no special significance should be placed upon whether or not a termis elaborated or discussed herein. In some cases, synonyms for certainterms are provided. A recital of one or more synonyms does not excludethe use of other synonyms. The use of examples anywhere in thisspecification including examples of any terms discussed herein isillustrative only, and is not intended to further limit the scope andmeaning of the disclosure or of any example term. Likewise, thedisclosure is not limited to various embodiments given in thisspecification.

Without intent to limit the scope of the disclosure, examples ofinstruments, apparatus, methods and their related results according tothe embodiments of the present disclosure are given below. Note thattitles or subtitles may be used in the examples for convenience of areader, which in no way should limit the scope of the disclosure. Unlessotherwise defined, technical and scientific terms used herein have themeaning as commonly understood by one of ordinary skill in the art towhich this disclosure pertains. In the case of conflict, the presentdocument, including definitions will control.

Additional features and advantages of the disclosure will be set forthin the description which follows, and in part will be obvious from thedescription, or can be learned by practice of the herein disclosedprinciples. The features and advantages of the disclosure can berealized and obtained by means of the instruments and combinationsparticularly pointed out in the appended claims. These and otherfeatures of the disclosure will become more fully apparent from thefollowing description and appended claims, or can be learned by thepractice of the principles set forth herein.

The present invention relates to creating hearing test methods that aremore rapid and encompass a broader range of audible frequencies relativeto traditional simultaneous masking tests, such as a psychophysicaltuning curve (PTC) or a masked threshold (MT) test.

Masking is a phenomenon that occurs across all sensory modalities whereone stimulus component prevents detection of another. The effects ofmasking are present in the typical day-to-day hearing experience asindividuals are rarely in a situation of complete silence with just asingle relevant signal occupying the sonic environment. The basilarmembrane running along the center of the cochlea, which holds thestructures responsible for neural encoding of mechanical vibrations, isfrequency selective. To this extent, the basilar membrane acts tospectrally decompose incoming sonic information whereby energyconcentrated in different frequency regions is represented to the brainalong different auditory fibers. It can be modeled as a filter bank withnear logarithmic spacing of filter bands. This allows a listener toextract information from one frequency band, even if there is strongsimultaneous energy occurring in a remote frequency region. For example,an individual will be able to hear both the low-frequency rumble of acar approaching whilst listening to someone speak at a higher frequency.As relates to spectral masking, relatively high energy maskers arerequired to mask signals when the masker and signal have differentfrequency content, but relatively low intensity maskers can mask signalswhen their frequency content is similar.

The ability of the auditory system to separate signals that differ infrequency can be described using the concept of the auditory filter thatacts similarly to a spectral filter in signal processing. Thecharacteristics of auditory filters can be measured, for example, byplaying a continuous tone at the center frequency of the filter ofinterest, and then measuring the masker intensity required to render theprobe tone inaudible as a function of relative frequency differencebetween masker and probe components. The resulting psychophysical tuningcurve (PTC), consisting of a frequency selectivity contour extracted viabehavioral testing, provides useful data to determine an individual'smasking contours. For example, turning now to FIGS. 2A and 2B, in oneembodiment of the test, a masking band of noise 202 is gradually sweptacross frequency, from below the probe frequency 203 to above the probefrequency. The user then responds when they can hear the probe and stopsresponding when they no longer hear the probe. This gives a jagged trace205 that can then be interpolated to estimate the underlyingcharacteristics of the auditory filter. Other methodologies known in theprior art may be employed to attain user masking contour curves. Forinstance, an inverse paradigm may be used in which a probe tone 206 isswept across frequency while a masking band of noise is fixed at acenter frequency 207 (known as a “masked threshold test” or “MT test”).

Patterns begin to emerge when testing listeners with different hearingcapabilities using the PTC test. Hearing impaired listeners have broaderPTC curves, meaning maskers at remote frequencies more strongly impactthe audibility of the probe tone. To this extent, each auditory nervefiber of the HI listener, compared to a normal hearing person, containsinformation from more distant neighboring frequency bands, resulting inincreasing off-frequency masking. When MT curves are segmented bylistener age, which is highly correlated with hearing loss as defined bypure tone threshold (PTT) data (FIG. 1A), there is a clear trend of thebroadening of MT curves with age, FIG. 1B.

However, although these simultaneous masking tests, administered inapproximately two minutes, provide rich hearing data in terms ofauditory masking—they only cover a limited frequency span. To cover thetypical audible spectrum for both ears, multiple tests within differentfrequencies ranges would have to be performed which takes up to thirtyminutes, an amount of time that would be impractical due to user hearingfatigue. This then leads to inaccurate results. An analysis of MT curvesas segmented by ages, and by extension, hearing capacity, yields aninteresting observation: the slope of the downward segment of the MTcurve, between [re F masker] values 1.0-1.5, has a significantcorrelation with hearing health. In some use cases, only specificaspects of the shape of the masked threshold curve, such as the slope,are of interest, rather than the more general shape in its entirety. Itmay possible to design a new hearing test paradigm that exploits thisfact and records only that data which relates to these specific aspectsof interest. By reducing the amount of data collected in each frequencyregion in this way, it may also be possible for the paradigm tocontinuously collect data on auditory masking across the auditoryspectrum

A new, faster and more comprehensive approach is illustrated in the flowchart in FIG. 3, denominated as a cross-frequency simultaneous masking(xF SM) paradigm. Generally, a threshold test, or an amplitudeadjustment by the user, may first be performed to determine maskeraudibility levels, 301. Masker audibility levels 301 can includemultiple different masker audibility levels for the user, e.g. measuringacross multiple points of the audible spectrum.

Subsequently, once a proper masker amplitude is determined, a signalprobe and a masker probe are kept at a fixed frequency ratio(F_(s)/F_(c))=r (labeled at 302), while the probes are swept 303 acrossthe audible spectrum, F (or across some other range of audiblefrequencies, e.g. from 500 Hertz (Hz) to 6 kilohertz (kHz)). Theamplitude of the masker probe is determined based on the maskeramplitudes from 301, e.g. it may remain constant during the entirety ofthe test or be modified following a specific rule, e.g. dependent onmasker frequency. The amplitude of the signal probe is varied inresponse to one or more inputs received from the user. For example, in aBekesy paradigm, a user presses and holds a button (or provides someother user response) as long as the signal probe is audible to the user.In response to receiving this user input, the amplitude of the signalprobe is decreased. When the user releases the button (or ceases toprovide the some other user response), indicating that the signal probeis no longer audible to the user, then the amplitude of the signal probeis increased. In this context, a lack of a button press (or a cessationof receipt of the user response) is a user input in the same way as abutton press (or receipt of user response) is a user input. In someembodiments, the rate at which the probe tone's amplitude is eitherincreased or decreased can be on the order of ±5 dB/sec. Thus, the probetone level is varied/adjusted in a linear fashion. In some embodiments,it is contemplated that the rate of change in probe tone amplitude isindependent of the different fixed frequency ratios r that may beutilized.

At the beginning of the xF SM test disclosed herein (i.e. when thesignal probe and masker probe are initially generated, prior tobeginning the user data collection and frequency sweeping), the probetone may typically be generated at some fixed level relative to that ofthe masker tone. For example, the probe tone can be generated 15 dBbelow the masker tone, although other offset values may be employedwithout departing from the scope of the present disclosure. In someembodiments, if the masker tone is determined in step 301 to be at ornear an audibility threshold level for the user or listener performingthe test, this offset arrangement might be expected to result in the xFSM test beginning with the signal probe being inaudible to the user—thatis, below their auditory threshold. In some embodiments, the initialamplitude offset between the signal probe and the masker probe candepend in part on the fixed frequency ratio r that will be employed forthe frequency sweeping of the xF SM test, such that the initialamplitude offset value results in a probe tone that is both likelyaudible to an average listener but also not too far from the perceptualthreshold—which generally depends on the choice of the ratio r.

As will be explained in greater depth below, the ratio r in someembodiments is between 1.0-1.5, although other ratio values arepossible. In general, the ratio r can be determined by beginning fromclassic MT curves, which provide a meaningful range of ratios that canthen be further limited, e.g. through an iterative and/or experimentalprocess. Based on data of MT tests that cover the full MT curve at asingle masker frequency, specific points can be identified that bestcorrelate with other hearing measures as they relate to individualusers. For example, auditory thresholds across frequency are one hearingmeasure that may be of particular utility in identifying thesecorrelation points.

At 304, whilst being swept at the fixed frequency ratio r, aBekesy-style approach is used to track the user's response to thestimuli provided by the swept probe tones—with the signal probe having avariable amplitude, dependent on user interaction, and the masker probekept at a predetermined amplitude. The frequency sweeping may then berepeated back and forth one or more times at 305, allowing for the userresponse(s) to be interpolated in generating an xF SM curve for theuser.

In some embodiments, the frequency sweeping described herein can beperformed with a variable rate of change in frequency. For example,consider a scenario in which frequency is swept from 500 Hz (lowerbound) to 6 kHz (upper bound). In some embodiments, the xF SM test (andhence, the frequency sweeping process) may begin at an intermediatefrequency value, e.g. a 2 kHz masker center frequency and an r*2 kHzsignal frequency. From this intermediate frequency value, and whilemaintaining the fixed frequency ratio r, the masker tone and signal toneare swept up (i.e. frequency increased) until the masker tone reachesthe maximum value given by the 6 kHz upper bound. While approaching theupper bound (or after reaching the upper bound), the rate of frequencyincrease slows until reaching zero, at which point frequency decreasebegins. From the upper bound, frequency is then swept down (decreased)until the masker tone reaches the minimum value given by the 500 Hzlower bound. While approaching the lower bound (or after reaching thelower bound), the rate of frequency decrease slows until reaching zero,at which point frequency is increased again until the masker tonereaches the initial intermediate value of 2 kHz. In some embodiments,the above described frequency sweeping process may be performed over thecourse of approximately 3 minutes per ear, per xF SM test—well below the30 minutes required by conventional MT hearing tests, as discussedpreviously. Note that in some embodiments, frequency may change morerapidly than in the above described example, in which case the amplitudeof the signal tone is varied more rapidly.

Although the description above references a scenario in which a singleratio r is used for the fixed frequency ratio between the signal probeand the masker probe, in some embodiments it is possible that multipleof the disclosed xF SM tests can be performed with different values forratio r. For example, multiple tests can be run for a given user, whereeach test has a different ratio r, e.g., r=1 for the first xF SM test,r=1.25 for the second xF SM test, and r=1.5 for the third xF SM test.For each xF SM test (or more generally, for each different ratio value rthat is used across the plurality of xF SM tests), a corresponding xF SMcurve can be generated. The plurality of xF SM curves generated fordifferent values of fixed frequency ratio r between the signal probe andthe masker probe can then be used to re-construct classic MT curves witha greater degree of confidence, accuracy and/or resolution than whenusing only a single xF SM curve for the classic MT curve reconstructionprocess.

Turning next to FIGS. 4A-C, a sequence depicting an example xF SM testis illustrated. The y-axis represents the amplitude of the depictedsignals, which include a noise masker probe M 404 and a tone signalprobe 403. The x-axis is logarithmic in frequency F. As illustrated,noise masker probe M 404 has a center frequency F_(c) and is kept atpredetermined amplitudes while being swept in frequency (i.e. the leftto right progression seen in the graphs of FIGS. 4A-C). In someembodiments, the absolute width of the masker probe M 404 is dynamic,e.g. 0.2 octaves on either side of the center frequency F_(c). Tonesignal probe 403 has a frequency F_(s) and a variable amplitude, i.e.,an amplitude that is varied or adjusted while tone signal probe 403 isbeing swept in frequency, with an example variability or range ofvariability illustrated via arrow 406. In some embodiments, the rate ofvariation of amplitude of tone signal probe 403 is independent of therate at which the masker probe 404 and tone signal probe 403 arefrequency swept, although in other embodiments a relationship iscontemplated, as will be explained in greater depth below. Whileperforming frequency sweeping of the tone signal probe 403 and themasker probe 404, a fixed frequency ratio r is maintained, indicated inFIGS. 4A-C at 402. In some embodiments, the fixed frequency ratio r isgiven by [F_(s)/F_(c)] where 1.0<r<1.5, although other ratio values,including values below 1.0, may be utilized without departing from thescope of the present disclosure. As illustrated, masker probe 404 andsignal probe 403 are then swept 405, 408 simultaneously to higherfrequencies while Bekesy-style user responses 407, 409 are recorded andthen interpolated to generate curve 401.

A similar, albeit converse, approach may be used for a PTC test. In thisinstance, the signal tone probe at frequency F_(s) is kept atpredetermined amplitudes while the noise masker probe M, at frequencyF_(m), has a user interaction-dependent, variable amplitude. Ratior=[F_(s)/F_(m)] is kept at a similar fixed value, e.g., between1.0<r<1.5. In some embodiments, the signal tone probe is kept above themasker probe in frequency, and the user controls the masker level (asopposed to the xF SM test, in which the user controls the signal level).

In either test, the user then responds when they can hear the probe andstops responding when they no longer hear the probe. This gives a jaggedtrace 504 that can then be interpolated to estimate the xF SM curve 503,as illustrated in FIGS. 5A-B. Moreover, the signal and masker probes,fixed apart at frequency ratio r, can be swept back and forth (e.g. 305of FIG. 3) across the audible spectrum to collect more data points.Significantly, the interpolated xF SM curves strongly match the resultof classic MT curves (FIGS. 6A-7B). FIG. 6A illustrates MT testsconducted three times in the left and right ears at center frequencies500 Hz, 1 kHz, 2 kHz and 4 kHz. FIG. 6B depicts three separate xF SMtests conducted in the left and right ears, illustrated at r=F_(s)/F_(c)ratios of 1, 1.25 and 1.5. When each of the curves for each respectivetest are averaged and then juxtaposed (as illustrated in FIGS. 7A-B), astrong relationship is observed in the mapping of xF SM curves at 1.0×(704), 1.25× (705) and 1.5× (706) ratios with the respective positionsof each MT curve.

As described in commonly owned U.S. application Ser. No. 16/080,785(“Method for accurately estimating a pure tone threshold using anunreferenced audio system”), an xF SM curve may be used to determine anaudiogram of the individual—in this instance by converting the xF SMcurve into a collection of MT curve or PTC across the audible spectrum(see FIGS. 7A-B). Due to the strong correlation of MT/PTC curves withpure tone threshold results, an estimate of the audiogram may be readilyderived.

Following the acquirement of hearing test data from the xF SM test, theresults may also be used to determine parameters for a processingfunction. Parameters may be calculated directly from a user's hearingdata or indirectly based on preexisting entries in a database.

Briefly, DSP parameters may be calculated indirectly based onpreexisting entries or anchor points in a server database (see commonlyowned U.S. application Ser. No. 16/540,345, “Systems and methods forproviding personalized audio replay on a plurality of consumerdevices”). An anchor point comprises a typical hearing profileconstructed of demographic information, such as age and sex—in which DSPparameter sets are calculated and stored on the server to serve asreference markers. Indirect calculation of DSP parameter sets bypassesdirect parameter sets calculation by finding the closest matchinghearing profile(s) and importing (or interpolating) those values for theuser. For instance, a root mean square difference calculation, aEuclidean distance calculation (or other statistical techniques commonlyknown in the art) may be employed to find the closest matching xF SMcurve for a user compared to an entry in a database— and the DSPparameters values associated with the closest matching curve may then beused for the user.

DSP parameters may also be calculated directly. This may be done using ahearing aid gain table prescriptive formulas. In another embodiment,ratio and threshold values for a compressor, as well as gain, in a givenmultiband dynamic processor signal subband may be calculated bycomparing user threshold and suprathreshold information for a listenerwith that of a normal hearing individual, i.e. reference audiograms andPTC/MT curves (see commonly owned U.S. Pat. No. 10,398,360, “Method toEnhance Audio Signal from an audio output device”). For instance,masking contour curve data, such as PTC or MT, may be used to calculateratio and threshold parameters for a given frequency subband, whileaudiogram data may be used to calculate gain within a given frequencysubband.

DSP parameters in a processing function may also be calculated byoptimizing perceptually relevant information (e.g. perceptual entropy)through parameterization using user xF SM hearing data (see commonlyowned U.S. Pat. No. 10,455,335 and pending U.S. application Ser. No.16/538,541, “Systems and methods for modifying an audio signal usingcustom psychoacoustic models”). Briefly, in order to optimallyparameterize a multiband dynamic processor through perceptually relevantinformation, an audio sample, or body of audio samples, is firstprocessed by a parameterized multiband dynamics processor and theperceptual entropy of the file is calculated according to user hearingdata. After calculation, the multiband dynamic processor isre-parameterized according to a given set of parameter heuristics,derived from optimization, and from this—the audio sample(s) isreprocessed and the PRI calculated. In other words, the multibanddynamics processor is configured to process the audio sample so that itachieves a target PRI value for the particular listener, taking intoaccount the individual listener's hearing profile. To this end,parameterization of the multiband dynamics processor is adapted toincrease the PRI of the processed audio sample over the unprocessedaudio sample. The parameters of the multiband dynamics processor aredetermined by an optimization process that uses a specific PRI target asits optimization criteria. In particular, if a measure similar toperceptual entropy is used as the PRI metric, the result of an xF SMtest may be used to derive the shape of the spreading function(s) acrossat least part of the audible range, which represents a central componentof a perceptual entropy calculation.

Other parameterization processes commonly known in the art may be usedto calculate parameters based off user-generated hearing data. Forinstance, common prescription techniques for linear and non-linear DSPmay be employed. Well known procedures for linear hearing aid algorithmsinclude POGO, NAL, and DSL. See, e.g., H. Dillon, Hearing Aids, 2ndEdition, Boomerang Press, 2012.

Subsequently, the parameters may be stored and/or outputted to a digitalsignal processing function.

The presented technology offers a more efficient and comprehensivehearing test methodology relative to traditional suprathreshold testingtechniques, such as MT or PTC testing. By concurrently sweeping a signalprobe and a masker probe at a fixed frequency ratio across the audiblespectrum using a cross-frequency simultaneous masking (xF SM) approach,more detailed hearing data may be acquired from a user in a shorterperiod of time—leading to richer or more accurate test results bymitigating user hearing fatigue. The rich hearing data resulting fromthis xF SM approach may then be used to calculate parameters for adigital signal processing function—or generally may be used to betterassess an underlying hearing impairment.

Methods according to the above-described examples can be implementedusing computer-executable instructions that are stored or otherwiseavailable from computer readable media. Such instructions can comprise,for example, instructions and data which cause or otherwise configure ageneral-purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.Portions of computer resources used can be accessible over a network.The computer executable instructions may be, for example, binaries,intermediate format instructions such as assembly language, firmware, orsource code. Examples of computer-readable media that may be used tostore instructions, information used, and/or information created duringmethods according to described examples include magnetic or opticaldisks, flash memory, USB devices provided with non-volatile memory,networked storage devices, and so on.

Devices implementing methods according to these disclosures can comprisehardware, firmware and/or software, and can take any of a variety ofform factors. Typical examples of such form factors include laptops,smartphones, small form factor personal computers, personal digitalassistants, rack-mount devices, standalone devices, and so on.Functionality described herein also can be embodied in peripherals oradd-in cards. Such functionality can also be implemented on a circuitboard among different chips or different processes executing in a singledevice, by way of further example. The instructions, media for conveyingsuch instructions, computing resources for executing them, and otherstructures for supporting such computing resources are means forproviding the functions described in these disclosures.

Although a variety of examples and other information was used to explainaspects within the scope of the appended claims, no limitation of theclaims should be implied based on particular features or arrangements insuch examples, as one of ordinary skill would be able to use theseexamples to derive a wide variety of implementations. Further andalthough some subject matter may have been described in languagespecific to examples of structural features and/or method steps, it isto be understood that the subject matter defined in the appended claimsis not necessarily limited to these described features or acts. Forexample, such functionality can be distributed differently or performedin components other than those identified herein. Rather, the describedfeatures and steps are disclosed as examples of components of systemsand methods within the scope of the appended claims.

What is claimed is:
 1. A method for conducting a cross frequencysimultaneous masking (xF SM) test, the method comprising: generating asignal probe and a masker probe, wherein a center frequency of thesignal probe and a center frequency of the masker probe are separated bya first fixed frequency ratio; for a given frequency range, generating afirst xF SM curve by: sweeping the signal probe and the masker probeacross the given frequency range while maintaining the first fixedfrequency ratio between the signal probe and the masker probe;maintaining the masker probe at a pre-determined masker amplitude;adjusting the amplitude of the signal probe in response to a series ofuser inputs; and interpolating the series of user inputs to generate thefirst xF SM curve.